Mucosal Immunization with a Conserved HIV Envelope Peptide Cocktail Vaccine

描述(由申请人提供)：迫切需要一种安全有效的艾滋病毒疫苗，可在世界大多数地区友好地使用，通过强大的粘膜和系统免疫来预防和/或治疗艾滋病毒感染。这项创新拨款提案将测试我们开发的高度保守的HIV包膜多肽鸡尾酒的潜力，该鸡尾酒与一种新型霍乱毒素突变体一起作为粘膜疫苗的佐剂，最好是通过口服途径。以前的研究表明，该多肽鸡尾酒通过静脉注射使用弗氏佐剂和/或自体树突状细胞预防接种，可保护恒河猴免受SHIVku2和SHIV89.6P的慢性感染和艾滋病。我们开发的霍乱毒素双密码子突变体CT2*是一种有效的佐剂，用于诱导HIV特异性黏膜和系统细胞免疫反应的HIV多肽鼻腔免疫小鼠。我们还观察到，用CTL表位多肽和CT2*口服免疫小鼠，在用重碳酸盐中和胃酸后，可以诱导抗原特异性的CTL反应。我们推测，高度保守的HIV包膜多肽鸡尾酒，当与CT2*结合时，将是一种通过鼻腔和口服进行粘膜免疫的有效疫苗。为了验证这一假设，我们将首先确认我们开发的霍乱毒素CT2*的两个密码子突变体在佐剂方面是否会优于另一个公认的单密码子突变体E112K。在此之后，我们建议在小鼠模型中进行比较分析，通过鼻腔和口服途径将多肽鸡尾酒与CT2*一起传递，以产生抗原特异性细胞免疫反应，并评估这些反应对编码HIV包膜蛋白的重组痘苗病毒攻击的保护效果。对于口服免疫，我们还建议测试一种策略，将疫苗多肽鸡尾酒封装在肠溶胶囊中，该胶囊设计为在消化轨迹中遇到酸时溶解，并将疫苗输送到肠道抗原递呈细胞(与贝勒医学院的迈克尔巴里博士合作)。从小鼠研究中选择的最佳粘膜给药策略(鼻腔或口服)将用于测试与CT2*佐剂混合的多肽鸡尾酒疫苗对恒河猴阴道内致病性SHV攻击的免疫原性和保护效力。这些研究的成功结果应该使我们能够制定多肽鸡尾酒粘膜疫苗的临床前开发计划。

DESCRIPTION (provided by applicant): A safe and effective HIV vaccine amicable for use in most parts of the world to prevent and/or treat HIV infection through strong mucosal and systemic immunity is an urgent need. This innovation grant proposal will test the potential of a highly conserved HIV envelope peptide cocktail we developed along with a novel cholera toxin mutant as adjuvant for mucosal vaccination, preferably by the oral route. Previous studies demonstrated that prophylactic vaccination with this peptide cocktail delivered by intravenous route using Freund's adjuvant and/or autologous dendritic cells protected rhesus macaques from chronic infection and AIDS by SHIVku2 and SHIV89.6P. A two-codon mutant of cholera toxin, CT2*, we developed (patent pending), was effective as adjuvant for intranasal immunization of mice with the HIV peptides for inducing HIV-specific mucosal and systemic cellular immune responses. We also observed that oral immunization of mice with a CTL-epitope peptide and CT2*, after neutralizing stomach acid with bicarbonate, resulted in induction of antigen-specific CTL responses. We hypothesize that the highly conserved HIV envelope peptide cocktail when combined with CT2* will be an efficient vaccine for mucosal immunization by intranasal as well as oral delivery. To test this hypothesis, we will first confirm whether the two-codon mutant of cholera toxin CT2* we developed will be superior to another well-established single-codon mutant E112K in terms of adjuvanticity. After this, we propose comparative analysis in the mouse model, for delivery of peptide cocktail along with CT2* by the intranasal and oral routes to generate antigen-specific cellular immune responses that will be assessed for protective efficacy against challenge with recombinant vaccinia virus encoding the HIV envelope protein. For oral immunization, we also propose to test a strategy involving encapsulation of the vaccine peptide cocktail in enteric-coated capsules that are designed to dissolve when encountered with acid in the digestive track and deliver the vaccine to intestinal antigen presenting cells (in collaboration with Dr. Michael Barry, Baylor college of Medicine). The optimal mucosal delivery strategy (intranasal or oral) selected from the mouse studies will be used for testing immunogenicity and protective efficacy of the peptide cocktail vaccine admixed with the CT2* adjuvant in rhesus macaques against intra-vaginal pathogenic SHIV challenge. Successful outcome in these studies should enable us to formulate pre-clinical development plan for mucosal vaccination with the peptide cocktail.